Counterbalanced relay



July 2, 1963 P. N. MARTIN COUNTERBALANCED RELAY 2 Sheets-Sheet 1 Filed April 26. 1960 INVENTOR. RQUL /X MAW-m A rrop/VEYS United States Patent O 3,096,412 COUNTERBALANCED RELAY Paul N. Martin, Frederick, Md., assigner to Consolidated Electronics Industries Corp., New York, N.Y., a corporation of Delaware Filed Apr. 26, 1960, Ser. No. 24,730 11 Claims. (Cl. 2011-87) This invention relates to counterbalancing structures tor relay armatures, and particularly to a pivoted counterbalance structure.

In accordance with the invention, the armature of a relay is balanced against gravitational and other linear, externally-applied forces by means of a weight pivotally attached to the armatune and subjected to substantially the same externally-applied forces as the armature. In one of its simplest forms the counterbalance weight is mounted on a pivot, the axis of which does not pass thro-ugh the center of gravity of the weight but is offset to one side. The weight is linked to the armature so that, as the armature moves in one direction, the weight -is pivoted to cause the heavier side thereof to move in substantially the oppo-site direction. Such an arrangement permits a countenbalance weight to be added to a relay without greatly increasing the overall dimensions of the relay and without interfering materially with the efliciency and other operating characteristics of the relay.

The invention will be further described in connection with the drawings in which:

FIG. 1 is a cross-sectional View of one embodiment of a relay constructed according to the invention;

FIG. 2 is a plan view of the armature and counterbalance Iweight of FIG. Il;

FIG. 3 is a `cross-sectional view of a different embodiment of the invention;

FIG. 4 is a plan view of the counterbalance weight of `FIG. 3; and

FIG. 5 is a partial view of a modification of the structure shown in fFlG. 3.

In FIG. 'l .a relay coil is indicated by reference chara-cter 11. The coil is mounted on a frame 12, normally of magnetically soft material, and surrounds a core 13, which extends through the coil "11 and is attached to the base 14 of the frame.

An armature l16 is attached to the `frame 1'4 in the manner indicated in U.S. Patent 2,913,548. Briefly, the armature is provided with a pair of corner, bent-over tabs 17 and 1S (only one of which appears in this figure) and these tabs, together with the under surface of the armature, proper, pivot about the edge 19 of the iframe 12. The armature is pressed into place by a resilient spring 21, which is attached to the frame 12 by machine screws 22, or any other convenient means, and extends out between the tabs 17 and 18 to a slight distance beyond the armature l16 where it is bent at approximately a right angle to extend along more or less parallel to the armature 116. Some distance r.trom the right angle bend, the spring is bent back on itself to contact the surtace of the armature, preferably close to .the region of the pivoting axis. An L-shaped member 23 is bent over after the armature is attached to hold the latter yfrom falling out under extraordinary mechanical jolts.

`Movement of the armature is transmitted via a `freely movable rod 24 to an assemblage of `contacts at the opposite end of the relay. It the relay is at rest or is in linear motion at la constant velocity, Ithe only motion of the armature will be that produced by the magnetic field induced in the core 14 when the coil 11 is energized by an electric current. However, relays are required in the operation of devices which do not remain stationary but which are subjected to external forces that cause the V'ice whole relay to accelerate. The term accelerate is used in the broad sense of a change in velocity of the relay. This includes causing the relay to move slower or to stop moving, as well as to move tE-aster. It includes causing the relay to begin moving from .a standstill. One of the most frequently-encountered types of acceleration is vibration. Another is mechanical impact, or shock. In any case, when the frame 12 accelerates, the motion, if suiciently rapid, 'will not be transmitted immediately to the armature, which will tend to remain stationary.

To clarify this, suppose the relay be suddenly accelerated upward in the direction of arrow 26. The edge 19 of .the lframe 12 will press upwardly on the pivot point of the armature 16. The center of mass of the armature is not located at the pivot point but, instead, is located to the right of it, as viewed in =FIG. 1. The upward pressure of lthe edge 19 will initially move the left hand end of the armature upward while the center of mass will `remain stationary because of its inertia. This is the same thing as saying that the free end armature 16 pivots downward in the direction of arrow 27, pressing upon the end of the contact actuator rod 24.

A collar 28 is attached to the lower end of the rod 214. This collar, which is preferably of insulating material, particularly if many contacts are to be actuated, extends out over the inwardly-directed ends of a number of resilient contact supports 29'. These contact supports are attached to pins 31 hermetically sealed in a support- -ing plate 32.

A spring 33 between the plate 32 and the collar 28 pushes on the latter land holds the rod 24 up against the stop 23. In Athis position the resilient supports 29 are Ifree to press up against upper, relatively stationary contacts 34 supported on pins 36 extending through the base 32 and insulated from it.

When the armature 16 presses down against the upper end of Ithe core 13, either because it is attracted by the magnetic eld of the core when the winding 11 is energized or because of some external force, .the collar 28 compresses the spring 33 and presses the ends of the resilient supports 29 so that the contacts carried thereon move away from the contacts 34 and down 'against the lower contacts 37 carried on the pins 38` in the base 32. The collar `28 is guided in its up and down movement by a pin 39 which extends through a guide hole in the collar and prevents the latter from rotating, as it would otherwise be free to do.

The tcounterbalancing structure for the relay of FIG. 1 comprises a -counterbalance weight 41 mounted on an axle 42 .about which it can pivot. The axle in turn, is carried in a pair of extensions 43 and 44, of which only extension 43 can be seen in FIG. l. These extensions are part of a partially cylindrical member 46 attached to the base 14 of the frame 12. The weight 41 has a pair of yarms 47 and 48 (only one of which is shown) connected together at their outer ends by la pin 49. This pin is part of a fork and pin linkage connecting the weight 41 to the armature 16. The fork part of this linkage consi-sts of the upper sur-tace of the armature 16 and a rigid member 51 attachedvto the armature by :rivets 52. fOne end of the member 511 is free and is spaced uniformly from the armature 16 to provide la slot of uniform width slightly greater than the diameter of the pin 49.

By virtue of the linkage between the armature 16 and the Weight 41, whenever the (free end of the armature pivots downward in the direction of the arrow 27, either because of magnetic attraction of the core 13 or because of the ,combination of external forces and tli'e inertia of the armature, the pin 49 and arms 47 and 48 will also be carried downward. As a result, the weight 41 will v the armature 56.

pivot upward in the direction of tihe arrow 53 on the axle 42. By concentrating the mass of the weight 41 on the opposite end from the arms 47 and 48 and lbalancing Ithe moment of inertia of the weight d1 against the moment of inertia of the armature 16, the tendency of the armature 16 to move relative to the rest of the relay under the influence of forces other than that of the niagneti-c eld of the core 13, i.e., :external forces, may be substantially eliminated. This is true because the sai-Ine external forces act on the weight 4,1 that act on the armature 16. Placing the armature 16 and the weight 41 in substantially the same plane, along with the pivot points of each makes it more certain that the same external forces will act on both. Furthermore even rotational forces, of acceleration, such as :might be encountered in a spinning rocket, may be substantially balanced out, since :any external force that tends to pivot the armature 16 lin one direction would either tend to pivot the weight 41 in the same direction, thereby balancing out any movement of either, or, depending on the location of the axis of rotation, would act on the masses of the armature 'and weight in a direction largely perpendicular to their direction of motion, thereby having little tendency to move the armature.

FIG. 2 is a cross-section view of the relay of FIG. 1 along the line 2--2 and amounts to a plan view of the armature 16 and counterbalance weight 41. The extensions 43 and 44 that hold the axle 42. about which the weight pivots are bent outward and then back, parallel to each other to furnish the Widest possible support for the axle within the limits of the can 54 in which the relay is enclosed to permit the coil 11 to be dropped into place after the metal parts have been assembled. It is thus possible to join the Imember 46 to the base 14 of the drame 12 by staking or other convenient means and then de-grease the whole metal structure before adding the coil 11. Two spacers 55 and 56 are provided to center the weight 41 and to keep it from -rubbing against the extensions 43 and 44.

The weight 41 extends almost to the cylindrical wall of t-he can 54, although it is to be noted that the diameter of the can is no lar-ger than would be required to house the same relay structure without the countenbalance assembly. Similarly, FIG. l shows that the can 54 need be little, if any, taller than would be required if the countenbalance assembly were omitted.

FIG. 3 shows a counterbalanced relay I-having la plunger type of armature 56 in contrast to the ciapper armature 16 of FIGS. l and 2. The plunger operates within the coil 57 and is attached to a rod 58 that operates la set of contacts similar to those of FIG. l but shown here in simplified form. The rod l58 carries a disc 59' that bears upon the free ends of resilient Contact members 61. The other ends of these contact members are attached to a rigid structure 62 immovable with respect to the coil S7. The resilient contact members operate between an upper position, `at which they connect with an upper set of relatively stationary contacts 63, and a lower position, at which they connect with a lower set of relatively stationary contacts 64.

The resilient members 61 are actuated by the collar 59, which moves when the rod 58 is moved up or down by Normally the rod is spring-biased to an upper position by a spring 66. The ferromagnetic armature 56 is moved downward by the magnetic field of the ferromagnetically soft core of the coil 57 when the latter is energized by an electric current. The core is divided into two hollow, cylindrical sections 67 and 63 separated by a gap 69. The inner diameter of the upper section 67 is large enough to permit the armature S6 to move freely, while the inner diameter of the lower section 68 need only be large enough to permit the rod 58 to pass through. Preferably the rod S is guided by upper -andlower journals 71 and 72, respectively, and

d is lirmly attached to the armature 56 so that the latter does not rub against the core 67.

The counterbalance mechanismy comprises n weight 73 pivoted at one side on an axle 74 that is rigidly supported with respect to the frame 76 of the relay. The rod 58 is linked to the weight 73 by an arm 77, which is rigidly attached to the rod 58 and is movably attached to the weight 73. The means connecting the weight and the arm is again a fork and pin device, las in FIG. l. Here, however, the pin 7S extends from the arm 73 and tbe fork is formed by rigid members 79 and 80 attached to the weight 73.

FIG. 4 shows a plan view of the weight 73 of FIG. 3, illustrating the way -it is attached to the arm 77. The weight, itself, is in the formof a `circular disc with a central aperture 81 through which the rod 58 passes. Two ears S2 and 83 extend out from one side of the disc to form, with the rigid members 79 and 80, the -fork in which the pin 78 is grasped. The end of the arm which carries the pin 78 extends between the ears 82 and 8B.

While the larm 77 is not in the plane of the weightr73, it may be placed in that position by cutting a channel of suiicient width in the weight at the proper location. This location would extend from the central aperture 81 nadially out between the ears 82 and 33. Of course, this would necessitate an obvious change in the suspension of the weight, since the axle 74 would have to be divided into two parts.

The relay in FIGS. 3 and 4 has a `direct connection between the armature 56 and the col-liar 59 that operates the resilient supports 61. While this is normally desirable because it eliminates lost motion, there may be circumstances in which it is desirable for the motion of the resilient supports to be in the opposite direction from that of the armature.

FIG. 5 shows a modification by which this reversal of direction may be obtained. The rod 158, corresponding -to the rod 58 of FIG. 3, terminates just below the armV 77. rBhe latter is connected to a weight 173, which is similar to the weight 73 of FIG. 3 except that it is directly, though somewhat loosely, attached to a rod 158a by retaining rigs 84 `and 86. These rings are spaced far enough Aapart to permit :the weight 173i to tilt on the rod la, as required. This rod corresponds to the lower end of the rod S3 oi FIG. 3. It is held in a downward position by a spring 166 which is under tension, rather than compression, so las to press the resilient contact supponts 61 against the lower contacts 64. In the energized state, the rod 158 moves downward and fthe counterballance weight 173 is pivoted upward, lifting the rod 158a and moving the resilient supports 61 up against the upper contacts 63. As before, lthe counter movement of the weight 173 balances the movement or the armature.

What is claimed` is:

l. A relay comprising: a winding; a ferromagnetic core energized by said winding to produce a magnetic field; :a clapper type armature pis/totally mounted to move about an axis rixed with respect to said core whereby one end of said armature moves with respect to said core under the force of attraction of a magnetic lield generated in said Winding; a counterbalance weight engaging said armature to be moved thereby, said weight being located in the same region of said relay as said :armature to vbe acted upc-n by substantially the same external fforccs that act Upon said armature and having a pivot axis 'which lies between the tiret-named `axis about which said armature pivots and ythe center of mass of said weight, the motion of said weight being aboutsaid pivot axis. l

2. The relay of claim 1 in which said axis about which said armature is pi'vortally mounted to move, said point of attachment of said weight to said armature, said pivot axis about which said weight moves, and said center of mass of said weight lie in approxi-mately the same plane.

3. The relay of claim lV in which said weight has a pair of arms extending cn opposite sides of said armature and lapproximately in the same plane as said armature and the center of mass of said Weight, and said arms comprise engagement means to engage said armature from the sides thereof and between the axis about which said armature pivots and the free end thereof.

4. A relay comprising: -a Winding; a lferromagnetic core energized by said Winding to produce a magnetic field; a clapper type armature pivotally mounted, near one of its ends, on a fulcrurn which is iixed with respect to said core, the end lof said armature away from said ulcrum being attracted to said core When the latter is energized by said winding; .a counterbalance Weight; iirst pivotal mounting means for said counteibal-ance Weight tol locate the weight in a position to be acted upon by substantially the same forces that act upon said armature except for the force of magnetic attraction between said core and said armature, the majority of the mass of said counter balance Weight being located lon one side of said pivotal mounting means; and second pivotal means Ilinking said counterbalance Weight to said :armature to cause said Weight to move simultaneously with said armature and in a direction to balance .the inertial force oi said armature.

5. A relay comprising a ferromagnetic core: a Winding surrounding said core; an armature located at yone end of said winding, one end of said armature being pivoted at one side ci said winding and the other end of said armature being tree to move towand said core in response to the magnetic field rof said core when said Winding is energized; a icounterb-alance 'weighltg pivotal mounting means therefor, said mounting means having a pivotal axis substantially parallel to the axis of pivotal movement of said armature, the majority of the mass of said Weight being on one side of said pivotal axis and being acted upon by snbstantially the same external itorces as said armatnre; and pivotal connecting means linking the porftion of said Weight on the `other side of said pivotal axis to said armature to cause said Weight to move simultaneously with said armature and .in a direction to balance the inertial forces of said armature.

6. Tlhe relay of claim 5 in which the pivotal mounting ot said armature and said pivotal axis are in substantially the same plane.

' 7. The relay of claim 5 in which said armature and said Weight are in substantially the saine plane.

8. The relay of claim 5 in which said plane is close to one end of said winding and substantially perpendicular to `the axis of said winding.

9. The device of claim 5 in which said pivotal connecting means linking said armature and said Weight comprises la fork and pin with the taxis `of said pin substantially parallel to said axis of pivotal movement of said armature.

10. A relay compris-ing: a coil; a tferromagnetically soft iron core `for said coil; :a clapper type :armature pivotably mounted near one end of said coil and having a free end attnaoted by said core when said coil is energized; a counterbalfance Weight; and iirst pivotal means mounting said countenbialance weight near .said end of said coil, the axis about which said weight pivots beingv close to said free end of said armature, the center of mass of said Weight being Kon the opposite side of said axis from said armature; `and second .pivotal means extending from said Weight toward said armature and engaging therewith to pivot said Weight vvhen said armature pivots, the moment of inertia of said Weight about the axis on which it pivots being substantially the same as the moment cf inertia of said armature on the axis about which it pivots and the direction olf movement of the center of mass of said weight is substantially opposite to the movement of the center of mass of said armature.

11. The relay according to claim 10 in which said core 'has a longitudinal passage therethrough; a rod extending through said passage `and longitudinally slideable therein, one end `ot" said rod extending from one end of said core and into contact with said armature to be moved by said armature; relatively iixed contact means; and relatively movable contact means engageable with said rod .to be moved into and out of connection with relatively iixed contact means, all of said contact means being located near the end ci said rod at .the `opposite end of said core from said armature.

References Cited in the file of this patent UNITED STATES PATENTS 706,083 Moskowitz Aug. 5, '19012 1,097,160: Balzer May 1'9, 19114 11,959,115 Taylor et al May 15, l1934 2,165,087 Ellis et al. July 4, 19'3-9 2,832,921 Hor-man Apr. 29, 1958 

1. A RELAY COMPRISING: A WINDING; A FERROMAGNETIC CORE ENERGIZED BY SAID WINDING TO PRODUCE A MAGNETIC FIELD; A CLAPPER TYPE ARMATURE PIVOTALLY MOUNTED TO MOVE ABOUT AN AXIS FIRXED WITH RESPECT TO SAID CORE WHEREBY ONE END OF SAID ARMATURE MOVES WITH RESPECT TO SAID CORE UNDER THE FORCE OF ATTRACTION OF A MAGNETIC FIELD GENERATED IN SAID WINDING; A COUNTERABALANCE WEIGHT ENGAGING SAID ARMATURE TO BE MOVED THEREBY, SAID WEIGHT BEING LOCATED IN THE SAME REGION OF SAID RELAY AS SAID ARMATURE TO BE ACTED UPON BY SUBSTANTIALLY THE SAME EXTERNAL FORCES THAT ACT UPON SAID ARMATURE AND HAVING A PIVOT AXIS WHICH LIES BETWEENT THE FIRST-NAMED AXIS ABOUT WHICH SAID ARMATURE PIVOTS AND THE CENTER OF MASS OF SAID WEIGHT, THE MOTION OF SAID WEIGHT BEING ABOUT SAID PIVOT AXIS. 